Question: $ { {-3} \times \left[\begin{array}{rr}{3} & {-2} \\ {-1} & {2} \\ {0} & {4}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-3}\times{3} & {-3}\times{-2} \\ {-3}\times{-1} & {-3}\times{2} \\ {-3}\times{0} & {-3}\times{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-9} & {6} \\ {3} & {-6} \\ {0} & {-12}\end{array}\right]}$